Thermodynamically and Dynamically Boosted Electrocatalytic Iodine Conversion with Hydroxyl Groups for High-Efficiency Zinc-Iodine Batteries.

Rechargeable zinc-iodine (Zn-I) batteries have shown immense potential for grid-scale energy storage applications, but there remain challenges of improving efficiency and cycling stability due to the sluggish iodine reduction reaction (IRR) kinetics and serious shuttle problem of polyiodides. We herein demonstrate an efficient metal-free hydroxyl (-OH)-functionalized carbon catalyst that effectively boosts the performance of Zn-I batteries. It has been found that the obtained electrocatalytic performance is strongly correlated with the surface oxygen chemical environment in the carbon matrix.